BugZilla issue 169: date header requirements

Hi,

below are proposed changes for Section 8, resolving Bugzilla issue 169 
(<http://ietf.cse.ucsc.edu:8080/bugzilla/show_bug.cgi?id=169>).

Section 8.5., para. 1:
OLD:

     HTTP defines many headers that can be used in WebDAV requests and
     responses.  Not all of these are appropriate in all situations and
     some interactions may be undefined.  Note that HTTP 1.1 requires the
     Date header in all responses if possible (see section 14.18,
     [RFC2616]).

NEW:

     HTTP defines many headers that can be used in WebDAV requests and
     responses.  Not all of these are appropriate in all situations and
     some interactions may be undefined.



Reason: it's unclear why we're saying something about "Date" 
specifically. So the easiest fix is not to do that at all. Otherwise, 
the statement needs to be at least correct, which it isn't (see 14.18 
for all the details).

PS: actually, I find the whole paragraph incredibly lame. It really 
doesn't say anything useful at all.

Best regards, Julian